Celebrating the physics of all that flows with Nicole Sharp, Ph.D.
- Profile
“Catalysis”
Catalysts speed up chemical reactions without being consumed themselves. In “Catalysis” the Beauty of Science team shows 5 different examples of catalytic reactions, from acetone oxidation to yeast fermentation. The film is full of bubbles, sparks, and wave-like pulses of chemical reaction. As always, it’s a lovely glimpse of processes we’re not used to watching…
Sand Traps
Antlion larvae catch prey by digging conical pits in sand. The steep walls of the trap are near the angle of repose, the largest angle a granular material can maintain before grains slide down. When a hapless ant wanders into the trap, the antlion throws sand from the center of the pit, triggering a sandslide…
Following the Flow
In early December 2020, the world’s largest iceberg — roughly 135 km long by 44 km wide — was heading straight for South Georgia Island. Luckily for the island, iceberg A-68A was being carried by ocean surface currents that approach the island before turning sharply southward. The enormous iceberg followed, rotating nearly 90 degrees and…
Uncovering Erosion Patterns
Gypsum and limestone cliffs sometimes form patterns of long, parallel grooves known as rillenkarren. Recent research shows that these patterns form when a thin layer of water flows over a dissolvable surface. As the running water picks up solute, its concentration increases, causing changes in the local hydrodynamics. What begins as a small perturbation in…
Breaking Bubbles
What do a nineteenth-century war ship, a sardine-hunting shark, and a viral bottle trick have in common? Cavitation! The phenomenon of cavitation occurs when a fluid is accelerated such that its local pressure drops below the vapor pressure. As a result, bubbles form and then violently collapse, creating shock waves that can damage nearby surfaces…
Bubble Array
Surface tension tries to minimize a bubble‘s surface area, which is why bubbles assume a spherical shape. But when many bubbles clump together, a curved interface is not always the most energy efficient one. In this case, bubbles can take on many shapes and sizes while still minimizing the overall surface energy. Take a close…
Hedgehogs Atop Waves
Since Michael Faraday, scientists have watched the curious patterns that form in a vibrating liquid. By adding floating particles to such a system, researchers have discovered spiky, hedgehog-like shapes that form near the surface. At low amplitudes, the surface patterns resemble the typical smooth rounded lobes one would expect, but as the wave amplitude increases,…
Stabilizing Foams
Bubbles in a pure liquid don’t last long, but with added surfactants or multiple miscible liquids, bubbles can form long-lasting foams. In soapy foams, surfactants provide the surface tension gradients necessary to keep the thin liquid layers between bubbles from popping. But what stabilizes a surfactant-free foam? New work finds that foams in mixtures of…
The Galloping Starfish
Starfish won’t win any sprints, but they’re actually quite good at moving around as they hunt for prey. Without brains, starfish are led by their feet, which pull in the direction of food they scent. Each foot is connected to what amounts to an internal hydraulic system within the starfish. With a combination of secreted…
Oil in Water
In the decade since the Deepwater Horizons oil spill, scientists have been working hard to understand the intricacies of how liquid and gaseous hydrocarbons behave underwater. The high pressures, low temperatures, and varying density of the surrounding ocean water all complicate the situation. Released hydrocarbons form a plume made up of oil drops and gas…